This image shows the micromotion machine and its experimental setup (left) and a geometric model used to convert plate motion to stem micromotion (right).
The tilt was assumed to occur at the center of the component. In a right triangle, the tilting angle (α) was calculated from the laser displacement (D), with sin α = D/L. In an isosceles triangle, the stem micromotion at the level of isthmus (dis) and micromotion at the stem tip (dt) were calculated from α (sin α/2 = [dis/2]/lis = [dt/2]/lt).
L is the radius of the plate (45 mm), lis is the length from the center to the isthmus (13 mm) and lt is the length of the stem (25 mm)